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標題: Observations on reaction pathways of dicobalt octacarbonyl with alkynyl amines
作者: Hong, F.E.
Huang, Y.L.
Chen, H.L.
關鍵字: cobalt-mediated catalytic reaction;carbonylation;azobenzene;Sanger's;reagent;catalytic oxidative carbonylation;selenium-assisted carbonylation;carbon-monoxide;cyclic ureas;aliphatic-amines;aromatic-amines;complexes;metal;aniline;alkoxycarbonylation
Project: Journal of Organometallic Chemistry
期刊/報告no:: Journal of Organometallic Chemistry, Volume 689, Issue 21, Page(s) 3449-3460.
Treatments of a bis(diphenylphosphino)methylene (dppm) bridged dicobalt complex, Co-2(CO)6(dppm) (4), with propargylamine and 4-ethynylaniline at 25 degreesC for 24 h gave [(dppm)Co-2(CO)(4)(mu-HCdropCCH(2)NH(2))] (5) and [(dppm)Co-2(CO)(4)(mu-HCdropCC(6)H(4)NH(2))] (6), respectively. Interestingly, only alkynyl amines bridged dicobalt complexes were obtained rather than the previously observed coupling products. The results are in acceptance with the proposed mechanism which describes the formation of the coupling products {[Co-2(CO)(6)(mu-HCdropC-)]-CH2NH}(2)C=O (1) and {[Co-2(CO)(6)(mu-HCdropC-)]-C6H4N=}(2) (2) from the reaction of Co-2(CO)(8) with propargylamine and 4-ethynylaniline, respectively. Similar results were attained for the reactions of 4 with propioamide and 1-ethynylcyclohexylamine at 25 degreesC for 24 h which yielded [(dppm)Co-2(CO)(4)(mu-HCdropCC(=O)NH2)] (7) and [(dppm)Co-2(CO)(4)(mu-HCdropCC(6)H(10)NH(2))] (8), respectively. Reaction of 1-ethynylcyclohexylamine with one molar equivalent of Co-2(CO)(8) in THF at 25 degreesC for 15 min gave an alkyne bridged dicobalt complex, [Co-2(CO)(6)(mu-HCdropCC(6)H(10)NH(2))] (9). Direct treatment of 3-ethynlaniline with one molar equivalent of Co-2(CO)(8) in THF at 25 degreesC for 1 h gave an alkyne bridged dicobalt complex, [Co-2(CO)(6)(mu-HCdropCC(6)H(4)NH(2))] (11) and an azobenzene derivative, {[Co-2(CO)(6)(mu-HC=C)]C6H4N=}(2) (10). Further treatments of 8, 9, and 11 with one molar equivalent of Sanger's reagent, 2,4-dinitrofluorobenzene, in THF at 25 C for 48 h gave [(dppm)Co-2(CO)(4)(mu-HCdropCC(6)H(10)NHC(6)H(3)(NO2)(2))] (13), [Co-2(CO)(6)(mu-HCdropCC(6)H(10)NHC(6)H(3)(NO2)(2))] (14), and [Co-2(CO)(6)(mu-HCdropCC(6)H(4)NHC(6)H(3)(NO2)(2))] (15), respectively. (C) 2004 Elsevier B.V. All rights reserved.
ISSN: 0022-328X
DOI: 10.1016/j.jorganchem.2004.07.047
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